Imparting magnetic properties to Fe—Si grain oriented steel is the most economical source of magnetic induction. From a chemical composition standpoint, adding silicon to iron is a very common way to increase electrical resistivity, hence improving magnetic properties, and reducing at the same time the total power losses. Two families presently co-exist for the construction of steels for electrical equipment: grain oriented and non oriented grain steels.
The so-called Goss texture {110}<001> conveys remarkable magnetic properties to the grain oriented steel when the crystallographic plane {110} is, ideally, parallel to the rolling plane and the crystallographic direction <001> is, ideally, parallel to the rolling direction. The latter rolling direction corresponds to the direction of easy magnetization.
The ferritic grains which constitute the matrix of Fe—Si grain oriented steels and have crystallographic orientations close to the ideal {110}<001> are usually called Goss grains.
The following properties are used to evaluate the efficiency of electrical steels when it comes to magnetic properties:                The magnetic induction, expressed in Tesla, which will be called J800 in this document as a reference to its measurement in an applied magnetic field of 800 A/m. Such value indicates how close the grains are to the Goss texture, the higher the better.        The core power loss, expressed in W/kg, measured at a specific magnetic induction expressed in Tesla (T) and working rate in Hertz. The lower the total losses, the better.        
A lot of metallurgical parameters may influence the above mentioned properties and the most common ones are: the material texture, the ferritic grain size, precipitates size and distribution, the material thickness, the isolating coating and an eventual superficial thermal treatment. Henceforth, the thermo-mechanical processing from the cast to an eventual superficial thermal treatment is essential to reach the targeted specifications.
On a one hand, regarding high magnetic flux density sheets, EP 2 077 164 discloses a method of production of grain oriented silicon grades with B10≧1.90 T using C: 0.010 to 0.075%, Si: 2.95 to 4.0%, acid soluble Al: 0.010 to 0.040%, N: 0.0010 to 0.0150% and one or both of S and Se in 0.005 to 0.1%, the balance being Fe and unavoidable impurities. The bar produced after casting has a thickness ranging between 20 and 70 mm. One of the following elements can be added in the chemical composition given above: Sb: 0.005 to 0.2%, Nb: 0.005 to 0.2%, Mo: 0.003 to 0.1, Cu: 0.02 to 0.2%, and Sn: 0.02 to 0.3%. The minimum temperature allowed before hot rolling is 1200° C. Such processing route is rather energy consuming since keeping a bar above 1200° C. or even 1250° C. after the cast would require more energy even if the bar is immediately hot rolled.
On the other hand, US 2009/0301157 relates to a method and a system for the production of hot-rolled strip silicon-alloy steel for further processing into grain-oriented sheets. The slab that is cast has a maximum thickness of 120 mm. The invention needs an intake temperature of the cast product into the hot-rolling line of at least 1200° C., and preferably in excess of 1250° C. No chemical composition is disclosed since the invention refers to a method and a system aiming at being multifunctional. The slab reheating, as mentioned before is an important step and is here twofold: A first preheating stage takes place and is followed by an intensive heating stage. Such processing route is rather energy consuming since the cast product shall be reheated in the intensive heating stage referenced as number 6 in the graph of the system lay out in the document.